Backend Engineer

Resend is building the most accessible email platform for developers. As we’ve grown to 4M+ users and continue to onboard thousands of new users every day, the pressure of maintaining a safe place for good senders continues to build.

This role is fully remote-based in Americas or European time zones, with some expected travel for team off-sites, conferences, meetups, and more.

Read more about how we work, how we hire, and what we value here.

In this role, you will…

• Build and operate Resend’s email transport infrastructure

• Work on SMTP delivery, MTA systems, routing, retries, backoff strategies, and delivery controls

• Design systems for domain-level, provider-level, customer-level, and IP-level throttling

• Build infrastructure for shared IP pools, dedicated IPs, warmup execution, and reputation-aware routing

• Improve how Resend classifies bounces, deferrals, transient failures, hard failures, and delivery outcomes

• Build tools that help the team debug delivery issues by customer, domain, mailbox provider, route, IP, message type, and event

• Help design systems that make sending behavior safer, more observable, and easier to operate

• Translate reputation strategy into backend systems

• Partner with Trust & Safety and Core Sending to build controls that protect Resend’s sending network from abuse

• Participate in incident response for sending, provider, and deliverability-sensitive issues

• Be on-call for critical services

You will be a great fit if you...

• Have strong backend engineering experience

• Have worked on email, messaging, notifications, communications, infrastructure, or other high-volume delivery systems

• Understand queues, workers, retries, idempotency, rate limits, backpressure, and distributed systems

• Have experience or strong interest in SMTP, MTAs, DNS, bounces, deferrals, DNS, IP pools, and mailbox-provider behavior

• Care about reliability, observability, operational excellence, and reducing blast radius

• Have low ego, high ownership, and strong taste for simple systems

You will be an exceptional fit if you also...

• Have experience working on applications with a high workload